/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.channel;

import io.netty.buffer.ByteBufAllocator;
import io.netty.util.AbstractConstant;
import io.netty.util.ConstantPool;
import java.net.InetAddress;
import java.net.NetworkInterface;

/**
 * A {@link ChannelOption} allows to configure a {@link ChannelConfig} in a type-safe way. Which
 * {@link ChannelOption} is supported depends on the actual implementation of {@link ChannelConfig}
 * and may depend on the nature of the transport it belongs to.
 *
 * @param <T> the type of the value which is valid for the {@link ChannelOption}
 */
public class ChannelOption<T> extends AbstractConstant<ChannelOption<T>> {

  private static final ConstantPool<ChannelOption<Object>> pool = new ConstantPool<ChannelOption<Object>>() {
    @Override
    protected ChannelOption<Object> newConstant(int id, String name) {
      return new ChannelOption<Object>(id, name);
    }
  };

  /**
   * Returns the {@link ChannelOption} of the specified name.
   */
  @SuppressWarnings("unchecked")
  public static <T> ChannelOption<T> valueOf(String name) {
    return (ChannelOption<T>) pool.valueOf(name);
  }

  /**
   * Shortcut of {@link #valueOf(String) valueOf(firstNameComponent.getName() + "#" +
   * secondNameComponent)}.
   */
  @SuppressWarnings("unchecked")
  public static <T> ChannelOption<T> valueOf(Class<?> firstNameComponent,
      String secondNameComponent) {
    return (ChannelOption<T>) pool.valueOf(firstNameComponent, secondNameComponent);
  }

  /**
   * Returns {@code true} if a {@link ChannelOption} exists for the given {@code name}.
   */
  public static boolean exists(String name) {
    return pool.exists(name);
  }

  /**
   * Creates a new {@link ChannelOption} for the given {@code name} or fail with an {@link
   * IllegalArgumentException} if a {@link ChannelOption} for the given {@code name} exists.
   */
  @SuppressWarnings("unchecked")
  public static <T> ChannelOption<T> newInstance(String name) {
    return (ChannelOption<T>) pool.newInstance(name);
  }

  public static final ChannelOption<ByteBufAllocator> ALLOCATOR = valueOf("ALLOCATOR");
  public static final ChannelOption<RecvByteBufAllocator> RCVBUF_ALLOCATOR = valueOf(
      "RCVBUF_ALLOCATOR");
  public static final ChannelOption<MessageSizeEstimator> MESSAGE_SIZE_ESTIMATOR = valueOf(
      "MESSAGE_SIZE_ESTIMATOR");

  public static final ChannelOption<Integer> CONNECT_TIMEOUT_MILLIS = valueOf(
      "CONNECT_TIMEOUT_MILLIS");
  /**
   * @deprecated Use {@link MaxMessagesRecvByteBufAllocator} and {@link MaxMessagesRecvByteBufAllocator#maxMessagesPerRead(int)}.
   */
  @Deprecated
  public static final ChannelOption<Integer> MAX_MESSAGES_PER_READ = valueOf(
      "MAX_MESSAGES_PER_READ");
  public static final ChannelOption<Integer> WRITE_SPIN_COUNT = valueOf("WRITE_SPIN_COUNT");
  /**
   * @deprecated Use {@link #WRITE_BUFFER_WATER_MARK}
   */
  @Deprecated
  public static final ChannelOption<Integer> WRITE_BUFFER_HIGH_WATER_MARK = valueOf(
      "WRITE_BUFFER_HIGH_WATER_MARK");
  /**
   * @deprecated Use {@link #WRITE_BUFFER_WATER_MARK}
   */
  @Deprecated
  public static final ChannelOption<Integer> WRITE_BUFFER_LOW_WATER_MARK = valueOf(
      "WRITE_BUFFER_LOW_WATER_MARK");
  public static final ChannelOption<WriteBufferWaterMark> WRITE_BUFFER_WATER_MARK =
      valueOf("WRITE_BUFFER_WATER_MARK");

  public static final ChannelOption<Boolean> ALLOW_HALF_CLOSURE = valueOf("ALLOW_HALF_CLOSURE");
  public static final ChannelOption<Boolean> AUTO_READ = valueOf("AUTO_READ");

  /**
   * If {@code true} then the {@link Channel} is closed automatically and immediately on write
   * failure. The default value is {@code true}.
   */
  public static final ChannelOption<Boolean> AUTO_CLOSE = valueOf("AUTO_CLOSE");

  public static final ChannelOption<Boolean> SO_BROADCAST = valueOf("SO_BROADCAST");
  public static final ChannelOption<Boolean> SO_KEEPALIVE = valueOf("SO_KEEPALIVE");
  public static final ChannelOption<Integer> SO_SNDBUF = valueOf("SO_SNDBUF");
  public static final ChannelOption<Integer> SO_RCVBUF = valueOf("SO_RCVBUF");
  public static final ChannelOption<Boolean> SO_REUSEADDR = valueOf("SO_REUSEADDR");
  public static final ChannelOption<Integer> SO_LINGER = valueOf("SO_LINGER");
  public static final ChannelOption<Integer> SO_BACKLOG = valueOf("SO_BACKLOG");
  public static final ChannelOption<Integer> SO_TIMEOUT = valueOf("SO_TIMEOUT");

  public static final ChannelOption<Integer> IP_TOS = valueOf("IP_TOS");
  public static final ChannelOption<InetAddress> IP_MULTICAST_ADDR = valueOf("IP_MULTICAST_ADDR");
  public static final ChannelOption<NetworkInterface> IP_MULTICAST_IF = valueOf("IP_MULTICAST_IF");
  public static final ChannelOption<Integer> IP_MULTICAST_TTL = valueOf("IP_MULTICAST_TTL");
  public static final ChannelOption<Boolean> IP_MULTICAST_LOOP_DISABLED = valueOf(
      "IP_MULTICAST_LOOP_DISABLED");

  public static final ChannelOption<Boolean> TCP_NODELAY = valueOf("TCP_NODELAY");

  @Deprecated
  public static final ChannelOption<Boolean> DATAGRAM_CHANNEL_ACTIVE_ON_REGISTRATION =
      valueOf("DATAGRAM_CHANNEL_ACTIVE_ON_REGISTRATION");

  public static final ChannelOption<Boolean> SINGLE_EVENTEXECUTOR_PER_GROUP =
      valueOf("SINGLE_EVENTEXECUTOR_PER_GROUP");

  /**
   * Creates a new {@link ChannelOption} with the specified unique {@code name}.
   */
  private ChannelOption(int id, String name) {
    super(id, name);
  }

  @Deprecated
  protected ChannelOption(String name) {
    this(pool.nextId(), name);
  }

  /**
   * Validate the value which is set for the {@link ChannelOption}. Sub-classes may override this
   * for special checks.
   */
  public void validate(T value) {
    if (value == null) {
      throw new NullPointerException("value");
    }
  }
}
